1. Field of the Invention
The present invention relates to a brake device in a buggy vehicle used mainly for traveling on an unleveled ground, and particularly, to a brake device for braking rear wheels in a buggy vehicle including a power unit, a propelling shaft connected to an output shaft of the power unit and extending longitudinally of the vehicle, a rear axle extending laterally of the vehicle, a reduction device which connects the propelling shaft and the rear axle to each other to reduce and transmit a power from the former to the latter, and a pair of left and right rear wheels each of which has a lower-pressure tire and which are mounted at opposite ends of the rear axle.
2. Description of the Related Art
In such buggy vehicle, it is especially required that the level of the brake device above the ground be set at as large a value as possible. so that a protrusion on the ground surface does not interfere with the brake device for the rear wheels during traveling of the vehicle on the unleveled ground. To meet such a requirement, a disk brake device has conventionally been proposed which includes a disk rotor secured to a propelling shaft for driving a rear axle at a reduced speed, as disclosed in Japanese Patent Application Laid-open No.60-163752. Such a brake device has an advantage that the torque transmitted to the propelling shaft is smaller than the torque applied to the axle and hence, the brake torque may be also relatively small and thus, it is possible to reduce the diameter of the disk rotor and to set the level of the brake device above the ground at a large value.
However, even though, the disk rotor mounted on the propelling shaft can be reduced in diameter, the whole brake torque must be produced by the single disk rotor and hence, there is a certain limit to the reduction in diameter. A disk brake having the disk rotor mounted on the propelling shaft is located at a position behind the power unit where it is hardly exposed to the wind produced by traveling of the vehicle. Therefore, a cooling property provided by the travel wind is far from an ideal level. Especially, if the disk brake is housed in a brake housing to prevent entering of the earth and sand, muddy water or the like, the reduction in cooling property of the brake device is inevitable.